Framing of joists in buildings



Feb. 10, 1970 PER-O. ON ETAL 3,494,087

FRAMING OF JOIS'IS IN BUILDINGS 2 SheetsSheet 1 Filed Jan. 12, 1967Fig.2

4 H H F 1N VE N TOR-S Feb. 10, 1970 PER-OLGF JONELL ET AL FRAMING OFJOISTS IN BUILDINGS 2 Sheets-Sheet 2 Filed Jan. 12, 1967 INVENTO SUnited States Patent 3,494,037 FRAMING OF JOISTS IN BUILDINGS Per-OlofJonell, Engelbrektsgatan 24, Goteborg, Sweden,

and Sven Melker Nilsson, Radhusvagen 6, Kallered,

Sweden Filed Jan. 12, 1967, Ser. No. 608,910 Claims priority,application Sweden, Jan. 25, 1966, 917/ 66 Int. Cl. E04f 15/18; E04b 1/8U.S. Cl. 52-403 5 Claims ABSTRACT OF THE DISCLOSURE The presentinvention has reference to an improved framing of joists having andintermediate layer of a soft material specially shaped for giving a goodsound insulation and having a low weight, while providing a two-stageshock-absorbing or compressibility factor under predetermined loadswherein the intermediate layer is of a construction and form whereby theinitial compression of said layer is greater for given smaller loadsapplied thereto than the subsequent or second stage compression forgiven greater loads applied thereto.

Framings of joists for house building purposes may in the same way aswalls be shaped either as a single or double construction. In the firstcase there is required e.g. in concrete framing of joists a weight ofthe same of at least 350-400 kg./m. if the requirements of a noiseinsulation should be fulfilled in Sweden. In the second case the weightof the framing of joists can be reduced in different degrees accordingto the type of construction. The layer situated between the upperconstruction portion, i.e. the floor proper, and the lower portion whichoften comprises a supporting portion is then of great importance. Thepurpose aimed at from the point of view of noise insulation is in thiscase that the intermediate layer should be as soft as possible. Whenthere is a question concerning walls which as a rule are not exposed togreat laterally directed forces, the intermediate layer may in thepractice be formed so soft that only the requirements on soundinsulation will influence the dimensioning. In practice the layer oftencomprises only an air layer. However, when there is a question offramings of joists, the conditions will be more complicated. In thiscase the intermediate layer must be apt to absorb vertical stressesentered into the framing of the joists without causing the floorcovering, e.g. a linoleum floorcloth, to burst or be damaged in anyother way when these forces must be taken into consideration whendimensioning the softness of the intermediate layer.

The present invention has reference to a framing of joists which iscomposed of a supporting lower portion and an overlaying fioorconstruction comprising e.g. a thin concrete slab and an intermediatelayer of an elastic material. The main feature of the invention is to beseen therein that the resilient device between the floor constructionand the lower portion is shaped in such a way that the downwarddeflection or compressibility-as seen from the original positionfor acertain charge or load increase will be considerably greater for smallloads on the floor construction than for high ones. The springing orresistance between the floor construction and the lower portion will beso soft that the noise insulation requirements can be fulfilled in spiteof a very low weight of the framing of joists. At small loads, say 50kg./rn. on the framing of joists, the springing can be made many timesgreater than at loads above this value. For 50 kg./m. the springing maybe eg about 1 millimeter but for a further load of 50 kg./m. only 0.1millimeter. In

3,494,087 Patented Feb. 10, 1970 this way it is possible to obtain avery good air and step noise insulation with a rather low weight of theframing of the joists, about kg./m. When the load increases to such avalue that it exceeds a value for which the springing is soft, thespringing does no longer have to be so soft for the reason that theincreasing load gives a sound insulating effect which compensates thelosses due to the harder or less resilient springing.

The invention will in the following be elucidated with reference to theaccompanying drawing showing a number of embodiments of the invention.In the drawings:

FIG. 1 is a side elevation of a joint between two concrete cassettes ina framing of joists provided with a device according to the invention,

FIG. 2 shows on an enlarged scale on the one hand a side elevation andon the other hand a vertical section through one of the cassettes,

FIG. 3 shows a similar section but when the floor construction isexposed to load,

FIG. 4 shows a section similar to the one in FIG. 2 but according toanother embodiment of the invention,

FIG. 5 is a plan view of one corner of the resilient intermediate layershown in FIG. 2,

FIG. 6 is a similar view of an intermediate layer but according toanother embodiment,

FIG. 7 shows on an enlarged scale a vertical section through one side ofthe framing of joists with a resilient intermediate layer according to afurther embodiment, and

FIG. 8 shows on an enlarged scale a vertical section through the upperleft hand corner of the embodiment shown in FIG. 2.

The framing of joists shown in the drawings is shown to comprise anumber of elements 1, 2 arranged close to each other and being carriedat their ends by a cross beam, a wall or a similar supporting element 3.In the space 4 between the elements 1, 2 there is inserted a tighteningor tieing means comprising an elastic material, e.g. synthetic resin, inthe shape of a hose 5 which from one end has been filled with a curingmass 6, e.g. concrete or synthetic resin. Each element 1, 2 comprises abowl-shaped concrete cassette 7, a thin layer 9 011 its upper smoothedborder 8 of any soft, resilient material such as cork, foamed plastics,rubber or the like and a thin concrete slab 10 covering the cassette orany other suitable floor construction. The slab 10 is self-supportingbetween the four side walls 11 of the cassette and rests on theresilient intermediate layer "9.

According to the embodiment shown in FIG. 2 the intermediate layer 9 isprovided with a ridge or bulge 12 extending in the longitudinaldirection. The width b (FIG. 8) and the height h of this ridge 12 ischosen in such a way that the desired softness is obtained for a certainload, e.g. 50 kg./m. When this load is exceeded, the ridge 12 will bepressed down into the elastic intermediate layer and the slab 10 willthereupon rest over the whole width B of the intermediate layer 9 (FIG.3). The height of the ridge 12 is chosen small, about 1 millimeter. Thevalue is chosen such that detrimental remaining deformations cannotoccur in the intermediate layer.

According to the embodiment shown in FIG. 4 the slab 1 0' is on itsunder side provided with a bulge 13 situated close to the outer borderand extending along said border. The dimensions of this bulge are chosenin such a way that at the predetermined low load, e.g. about 50 kg./m.the bulge 13 will be pushed practically completely down into the elasticintermediate layer 9 and at an increasing load the slab 10" will rest inflat shape against the whole upper side of the intermediate layer.

An analogous result can be obtained if instead the lower side of theintermediate layer 9 is provided with said bulge 12. One or severalbulges may be provided and these bulges can be formed by providingnotches in the upper or/and lower surfaces of the layer. At a certainlow load the slab rests against only the upwardly extending bulgesagainst the upper border of the cassettes 7 and resiliency will then bevery soft, At a greater load the bulges are pressed into theintermediate layer and the slab will then rest against the whole widthof the intermediate layer or this layer with the whole of its widthagainst the upper border of the cassettes.

The embodiment shown in FIG. 6 is provided with bulges comprisingabutment 14 of a low height, e.g. l millimeter. The transversedimensions of the abutments 14 and their mutual distance are chosen insuch a way that the abutments at the low load in question will bepressed practically completely into the intermediate layer 9 and at anexceeding of this load the slab 10 will rest on the whole of the upperside of the intermediate layer.

According to a further embodiment (FIG. 7) the intermediate layer 9comprises a strip of cork or cardboard and there is on one or both sidesof this strip attached a layer of grains of sand with a size of thegrains of about 1 millimeter in diameter. The sand grains may withadvantage be attached to the intermediate layer 9 by means of abituminous binding agent. The distance between the grains is chosen inthe same way as described in the aforegoing in connection with theabutments 14 on the intermediate layer 9 according to FIG. 6.

According to FIG, 1 there is shown on the concrete slab 10 of theelements 1 and Z a linoleum floorcloth 16. Due to the rather lowspringing down at high loadsthere is as a rule a question of aresiliency in downwards direction of about 1 millimeter-there is no riskthat the fioorclothing will burst at the joint between the elements.

The invention has been described in the aforegoing for purposes ofillustration only and many modifications are possible within the scopeof the appended claims. Thus, the element parts 1, 2 as well as theintermediate layer 9 on the same way may be shaped in many differentways. Also other materials than the ones mentioned in the foregoingcould be used for the construction details mentioned. It is alsopossible to arrange the ridges, the bulges and the abutments on theupper side of the walls 11 of the cassettes.

What we claim is:

1. A framing of joists comprising a primarily supporting lower portion,a floor construction, an elastic intermediate layer supporting saidfloor construction on said lower portion, and resilient means betweensaid floor construction and said lower portion so shaped that thedownward give of said floor construction, as seen from the originalposition, for a certain load increase will be considerably greater forsmaller loads on the floor construction than for higher loads, andwherein there are provided projections between said floor constructionand lower portion having surfaces carrying said floor construction whenunder small loads, and said projections being compressed into the restof said elastic intermediate layer at a certain load increase.

2. A framing of joists as defined in claim 1 wherein said projectionscomprise grains embedded in said elastic intermediate layer, saidgrains, when the floor construction is in an unloaded condition,extending with a part of their volume outside of a surface of saidintermediate layer.

3. A framing of joists as defined in claim 1 wherein said projectionsare formed directly on said elastic intermediate layer in the shape ofabutments.

4. A framing of joists as defined in claim 1 wherein said projectionsare formed directly in said intermediate layer in the shape of aplurality of compressible bulges.

5. A framing of joists as claimed in claim 1 wherein said projectionsare provided On the underside of said floor construction.

References Cited UNITED STATES PATENTS 926,773 7/1909 Schirra 52-4452,425,567 8/ 1947 Robinson 248-22 2,962,183 11/1960 Rill et 211.

3,332,646 7/ 1967 Kellett 248-22 498,344 5/ 1 893 Williams 5 2-4031,937,186 11/1933 Barrett 52-502 2,746,097 5/1965 Tofani 52-403 FOREIGNPATENTS 730,018 3/ 1966 Canada.

472,499 9/ 1937 Great Britain.

554,818 7/1943. Great Britain.

FRANK L. ABBOTT, Primary Examiner J. L. RIDGILL, JR., Assistant ExamineriU.S. Cl. X.R. 52-414

